The discovery of an apparently positive latitudinal gradient in nematode species richness over a limited geographic area in the North Atlantic, leading to the hypothesis that it is associated with a positive latitudinal organic flux gradient, has created some debate. A test of this hypothesis is that the negative latitudinal organic flux gradient in the central equatorial Pacific should lead to an associated negative gradient in species richness. Here, we show that species richness in the central equatorial Pacific is positively associated with the organic flux predicted from the pattern reported for the North Atlantic. The patterns in nematode species richness differ from other deep-sea organisms; they seem to be entirely related to modern ecology and unaffected by historical events.

Lizards and snakes (squamate reptiles) are the most diverse vertebrate group in Australia, with approximately 1000 described species, representing about 10% of the global squamate diversity. Squamates are a vital part of the Australian ecosystem, but their conservation has been hindered by a lack of knowledge of their diversity, distribution, biology and key threats. The Action Plan for Australian Lizards and Snakes 2017 provides the first comprehensive assessment of the conservation status of Australian squamates in 25 years. Conservation assessments are provided for 986 species of Australian lizards and snakes (including sea snakes). Over the past 25 years there has been a substantial increase in the number of species and families recognised within Australia. There has also been an increase in the range and magnitude of threatening processes with the potential to impact squamates. This has resulted in an increase in the proportion of the Australian squamate fauna that is considered Threatened. Notably over this period, the first known extinction (post-European settlement) of an Australian reptile species occurred – an indication of the increasingly urgent need for better knowledge and management of this fauna. Six key recommendations are presented to improve the conservation management and plight of Australian squamates. This Action Plan represents an essential resource for research scientists, conservation biologists, conservation managers, environmental consultants, policy makers from Commonwealth and State/Territory governments, and the herpetological community.

Laboratory studies of terrestrial-breeding frogs have demonstrated that wetter substrates produce ¢tter o¡spring but the relevance of substrate wetness to adult reproductive strategies is unknown. I hypothesized that male toadlets (Pseudophryne bibronii) would select wetter areas for nesting and would advertise wet nests strongly, and tested these predictions by manipulating water potentials at a breeding site. Males preferred to nest in the wettest areas, and called at greater rates on almost twice as many nights as males occupying drier nests. Overall, males that mated called on signi¢cantly more nights than unmated males. Hence, because males occupying wet nests called more, they also mated more and in 19 out of 20 cases, oviposition occurred in wet nests that were suitable for embryonic development. Males occupying drier nests may have risked dehydration by calling, and so were less able to signal to females. Hydration states therefore have the potential to in£uence the reproductive success of terrestrial male frogs.

This paper supports the hypothesis that low oxygen does not in#uence deep-sea nematode abundance by investigating an oxygen minimum zone (OMZ) on the Oman slope in the Arabian Sea. Correlation with a number of environmental variables indicated that food quality (measured as the hydrogen index) rather than oxygen was the major predictor of nematode abundance. Nematode abundance was also positively correlated with abundance of total macrofauna, annelids, spionid polychaetes and macrofaunal tube builders. Comparison with published data showed Arabian Sea nematode abundance to be similar to that of the Porcupine Seabight and Bay of Biscay regions of the northeast Atlantic, which also receive signi"cant quantities of phytodetritus but have no OMZ.

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